Novel popout without novelty

Localization of a novel word in an array with several familiar words is typically enhanced relative to localization in an all-novel array (between-array novel popout) and sometimes enhanced relative to familiar words in one-novel arrays (within-array novel popout). Christie and Klein (1996) have questioned the reality of the latter effect, suggesting that it may be an artifact of guessing bias. The present Experiment 1 replicated within-array novel popout with the novel word probed at chance (i.e., on only one quarter of trials). Experiments 2 and 3 demonstrated a similar popout effect for a categorically unrelated word among three categorically related words, despite superior performance on all-related arrays relative to all-unrelated arrays. Repetition of constant sets of words within the experimental context is therefore unnecessary for a popout effect, contrary to assertions by Johnston and Hawley (1994). Interitem associations appear to be sufficient to produce a popout effect; as such, “novel popout” appears to be a misnomer for a phenomenon that does not depend on novelty.     

Novel popout with nonsense strings: Effects of predictability of string length and spatial location

Recent studies have shown that when one of four expected words is replaced by a single unexpected word, the unexpected word may capture attention. In three experiments, we explored the generality of this effect. In each experiment, observers viewed arrays composed of four computergenerated “nonsense” strings. Accuracy of string localization was assessed after each array. Some strings, calledfamiliar, appeared in many arrays, whereas others, callednovel, appeared in only one. In each experiment, novel strings in arrays composed of one novel and three familiar strings were localized more accurately than were novel strings in arrays composed entirely of novel strings, and familiar strings in these arrays were localized less accurately than were familiar strings in arrays composed entirely of familiar strings. These two effects, termednovel popout andfamiliar sink-in, respectively, were observed even when novel and familiar strings were rendered less discriminable by holding their lengths constant (Experiment 2) and when familiar strings always appeared in the same spatial locations (Experiment 3). The data suggest that novel objects can capture attention even when the objects lack any clear linguistic referent, when they are superficially similar to the familiar objects that surround them, and when the spatial locations of familiar objects are completely predictable.     

Novel popout and familiar popout in a brightness discrimination task

A single novel word among several familiarized words may be localized more effectively than the familiarized words (novel popout). Early demonstrations of novel popout attributed the effect to the capture of attentional resources by novel stimuli. Christie and Klein (1995, 1996) argued that differential recollection of novel versus familiar words could alternatively account for the popout effect. In the present experiments, participants judged which of four locations contained a physically brighter word. A bright novel word was localized significantly better than a bright familiar word in one-novel/three-familiar arrays, inconsistent with a retrievability account of novel popout. However, a bright familiar word was also localized better than a bright novel word in three-novel/one-familiar arrays, inconsistent with the mismatch theory proposed by Johnston and Hawley (1994). The results suggest that familiarity and novelty provide a perceptual segregation of the odd item; superior brightness discrimination at that location may be due either to attentional capture or to locational ambiguity within the larger group.     

Novel popout is an attention-based phenomenon: an ERP analysis

When observers are given a brief glimpse of a display containing one novel object and three repeated objects, they are often better able to report the location of the novel object than the location of any one of the repeated objects. The present study contrasted two interpretations of this "novel popout" effect. The attention-based interpretation suggests that the novel popout is an attentional phenomenon, occurring during the initial processing of the four-object display. The retrieval-based interpretation suggests that novel popout is due to differential processing occurring when observers are subsequently probed for the location of one of the objects in the display. ERP measures recorded while subjects performed the novel popout task revealed differences during the initial processing of the four-object display but not subsequent to the presentation of a localization probe. The findings are most consistent with the attention-based interpretation of novel popout, which suggests that attention is rapidly drawn to the novel object in an otherwise familiar display.     

Phonological decoding or direct access? Regularity effects in lexical decisions of Grade 3 and 4 children

Learning to read fluently involves moving from an effortful phonological decoding strategy to automatic recognition of familiar words. However, little is known about the timing of this transition, or the extent to which children continue to be influenced by phonological factors when recognizing words even as they progress in reading. We explored this question by examining regularity effects in a lexical decision task, as opposed to the more traditionally used reading-aloud task. Children in Grades 3 and 4 made go/no-go lexical decisions on high- and low-frequency regular and irregular words that had been matched for consistency. The children showed regularity effects in their accuracy for low-frequency words, indicating that they were using phonological decoding strategies to recognize unfamiliar words. The size of this effect was correlated with measures of reading ability. However, we found no regularity effects on accuracy for high-frequency words or on response times for either word type, suggesting that even 8-year-old children are already relying predominantly on a direct lexical strategy in their silent reading of familiar words.     

The neural substrates of action retrieval: An examination of semantic and visual routes to action

We report three PET experiments that examine the neural substrates of the conceptual components of action retrieval. In all three experiments, subjects made action or screen-size decisions to familiar objects presented either as pictures or written words (the names ofthe objects). In Experiment 1, a third task was included, requiring a decision on the real-life size of the stimuli. In Experiment 2, a third stimulus type was included, with action and size decisions also performed on pictures of meaningless novel objects. Finally, in Experiment 3, we changed the response mode from a button press to a more explicit movement made with a “manipulandum”. Based on neuropsychological findings, we predicted that when action responses were made to pictures of familiar or novel objects, relative to words, there would be less activation in semantic regions but greater activation in visual, motor, and perhaps parietal cortices. We found that, action relative to screen-size decisions on both pictures and words activated the left hemisphere temporo-frontal semantic system with activation in the left posterior middle temporal cortex specific to action retrieval (Experiment 1). In addition, action retrieval elicited more activation for (1) words than pictures in areas associated with semantics; and (2) novel objects than words or familiar objects in areas associated with pre-semantic object processing. These results are discussed in the context of semantic and visual routes to action retrieval.     

Listen to your mother! The role of talker familiarity in infant streaming

Little is known about the acoustic cues infants might use to selectively attend to one talker in the presence of background noise. This study examined the role of talker familiarity as a possible cue. Infants either heard their own mothers (maternal-voice condition) or a different infant's mother (novel-voice condition) repeating isolated words while a female distracter voice spoke fluently in the background. Subsequently, infants heard passages produced by the target voice containing either the familiarized, target words or novel words. Infants in the maternal-voice condition listened significantly longer to the passages containing familiar words; infants in the novel-voice condition showed no preference. These results suggest that infants are able to separate the simultaneous speech of two women when one of the voices is highly familiar to them. However, infants seem to find separating the simultaneous speech of two unfamiliar women extremely difficult.     

Linguistic and conceptual influences on adjective acquisition in 24- and 36-month-olds

Two hundred forty English-speaking toddlers (24- and 36-month-olds) heard novel adjectives applied to familiar objects (Experiment 1) and novel objects (Experiment 2). Children were successful in mapping adjectives to target properties only when information provided by the noun, in conjunction with participants' knowledge of the objects, provided coherent category information: when basic-level nouns or superordinate-level nouns were used with familiar objects, when novel basic-level nouns were used with novel objects, and--for 36-month-olds--when the nouns were underspecified with respect to category (thing or one) but participants could nonetheless infer a category from pragmatic and conceptual knowledge. These results provide evidence concerning how nouns influence adjective learning, and they support the notion that toddlers consider pragmatic factors when learning new words.     

Visual tracking and existence constancy in 5-month-old infants

Visual fixation and cardiac deceleration for 36 infants 20–24 weeks old were recorded during three kinds of events in which objects moving on a linear trajectory were temporarily occluded by a screen: (1) a familiar object appeared on both sides of the screen; (2) a novel object appeared on both sides of the screen; and (3) a novel object appeared to change to a familiar one behind the screen. Infant attention was related to novelty and familiarity of objects and there was no evidence of behavior reflecting the expectancy that a stable object continued to exist behind the screen. These findings are in conflict with those of previous tracking studies and the discussion focuses upon explanations for this discrepancy.     

The influence of novelty and complexity on exploratory behavior in 12-month-old infants

This study investigated the influence of the novelty of the environment and the novelty and complexity of the objects (toys) it contained on the exploratory behavior of 12-month-old infants. Each infant was given a choice between novel and familiar toys located in two adjacent rooms (toy rooms). The novelty of the objects was manipulated by allowing the infants to play with one set of toys during a 5-min familiarization trial prior to the choice trial. The novetly of the environment was manipulated by allowing some infants to see, enter, and remain in the toy rooms during the familiarization trial. Finally, the complexity of the objects was manipulated by varying the number of familiar and novel toys; some Ss had four toys in each set (complex array) and some had only one (simple array). The results indicate that all three factors influenced the infants' exploratory behavior. Ss first approached, and spent more time manipulating, the novel than the familiar toys; they spent more time in the toy rooms if they were novel; and they spent more time manipulating the complex array of toys than the simple array.     

Cross-modal working memory binding and L1-L2 word learning

The ability to create temporary binding representations of information from different sources in working memory has recently been found to relate to the development of monolingual word recognition in children. The current study explored this possible relationship in an adult word-learning context. We assessed whether the relationship between cross-modal working memory binding and lexical development would be observed in the learning of associations between unfamiliar spoken words and their semantic referents, and whether it would vary across experimental conditions in first- and second-language word learning. A group of English monolinguals were recruited to learn 24 spoken disyllable Mandarin Chinese words in association with either familiar or novel objects as semantic referents. They also took a working memory task in which their ability to temporarily bind auditory-verbal and visual information was measured. Participants’ performance on this task was uniquely linked to their learning and retention of words for both novel objects and for familiar objects. This suggests that, at least for spoken language, cross-modal working memory binding might play a similar role in second language-like (i.e., learning new words for familiar objects) and in more native-like situations (i.e., learning new words for novel objects). Our findings provide new evidence for the role of cross-modal working memory binding in L1 word learning and further indicate that early stages of picture-based word learning in L2 might rely on similar cognitive processes as in L1.     

Naming and Exclaiming: Infants' Sensitivity to Naming Contexts

In three experiments, we examined 17-month-olds' acquisition of novel symbols (words and gestures) as names for object categories. Experiment 1 compares infants' extension of novel symbols when they are presented within a familiar naming phrase (e.g., "Look at this [symbol]!") versus presented alone (e.g., "Look! ... [symbol]!") Infants mapped novel gestures successfully in both naming contexts. However, infants mapped novel words only within the context of familiar naming phrases. Thus, although infants can learn both words and gestures, they have divergent expectations about the circumstances under which the 2 symbolic forms name objects. Experiments 2 and 3 test the hypothesis that infants' expectations about the circumstances under which words that name objects are acquired by monitoring how adults indicate their intention to name. By employing a training paradigm, these two experiments demonstrated that infants can infer how an experimenter signals his or her intention to name an object on the basis of a very brief training experience.     

Changing within-trial array location and target object position enhances rats’ (Rattus norvegicus) missing object recognition accuracy

Six rats were trained to find a previously missing target or 'jackpot' object in a square array of four identical or different objects (the test segment of a trial) after first visiting and collecting sunflower seeds from under the other three objects (the study segment of a trial). During training, objects' local positions within the array and their global positions within the larger foraging array were varied over trials but were not changed between segments within a trial. Following this training, rats were tested on their accuracy for finding the target object when a trial's test array was sometimes moved to a different location in the foraging arena or when the position of the target object within the test array had been changed. Either of these manipulations initially slightly reduced rats' accuracy for finding the missing object but then enhanced it. Relocating test arrays of identical objects enhanced rats' performance only after 10-min inter-segment intervals (ISIs). Relocating test arrays of different objects enhanced rats' performance only after 2-min ISIs. Rats also improved their performance when they encountered the target object in a new position in test arrays of different objects. This enhancement effect occurred after either 2- or 30-min ISIs. These findings suggest that rats separately retrieved a missing (target) object's spatial and non-spatial information when they were relevant but not when they were irrelevant in a trial. The enhancement effects provide evidence for rats' limited retrieval capacity in their visuo-spatial working memory.     

On the limits of infants' quantification of small object arrays

Recent work suggests that infants rely on mechanisms of object-based attention and short-term memory to represent small numbers of objects. Such work shows that infants discriminate arrays containing 1, 2, or 3 objects, but fail with arrays greater than 3 [Feigenson, L., & Carey, S. (2003). Tracking individuals via object-files: Evidence from infants' manual search. Developmental Science, 6, 568-584; Feigenson, L., Carey, S., & Hauser, M. (2002). The representations underlying infants' choice of more: Object files versus analog magnitudes. Psychological Science, 13(2), 150-156]. However, little is known about how infants represent arrays exceeding the 3-item limit of parallel representation. We explored possible formats by which infants might represent a 4-object array. Experiment 1 used a manual search paradigm to show that infants successfully discriminated between arrays of 1 vs. 2, 2 vs. 3, and 1 vs. 3 objects. However, infants failed to discriminate 1 vs. 4 despite the highly discriminable ratio, providing the strongest evidence to date for object-file representations underlying performance in this task. Experiment 2 replicated this dramatic failure to discriminate 1 from 4 in a second paradigm, a cracker choice task. We then showed that infants in the choice task succeeded at choosing the larger quantity with 0 vs. 4 crackers and with 1 small vs. 4 large crackers. These results suggest that while infants failed to represent 4 as “exactly 4”, “approximately 4”, “3”, or as even as “a plurality”, they did represent information about the array, including the existence of a cracker or cracker-material and the size of the individual objects in the array.     

Pictures and words in visual search

Ss in three experiments searched through an array of pictures or words for a target item that had been presented as a picture or a word. In Experiments I and II, the pictures were line drawings of familiar objects and the words were their printed labels; in Experiment III, the stimuli were photographs of the faces of famous people and their corresponding printed names. Search times in Experiments I and II were consistently faster when the array items were pictures than when they were words, regardless of the mode of the target items. Search was also faster with pictures than with words as targets when the search array also consisted of pictures, but target mode had no consistent effect with words as array items. Experiment III yielded a completely different pattern of results: Search time with names as targets and faces as search array items was significantly slower than in the other three conditions, which did not differ from each other. Considered in relation to several theories, the results are most consistent with a dual-coding interpretation. That is, items that are cognitively represented both verbally and as nonverbal images can be searched and compared in either mode, depending on the demands of the task. The mode actually used depends on whether the search must be conducted through an array of pictures or words.     

Choosing your informant: weighing familiarity and recent accuracy

In two experiments, children aged 3, 4 and 5 years (N= 61) were given conflicting information about the names and functions of novel objects by two informants, one a familiar teacher, the other an unfamiliar teacher. On pre‐test trials, all three age groups invested more trust in the familiar teacher. They preferred to ask for information and to endorse the information that she supplied. In a subsequent phase, children watched as the two teachers differed in the accuracy with which they named a set of familiar objects. Half the children saw the familiar teacher name the objects accurately and the unfamiliar teacher name them inaccurately. The remaining half saw the reverse arrangement. In post‐test trials, the selective trust initially displayed by 3‐year‐olds was minimally affected by this intervening experience of differential accuracy. By contrast, the selective trust of 4‐ and 5‐year‐olds was affected. If the familiar teacher had been the more accurate, selective trust in her was intensified. If, on the other hand, the familiar teacher had been the less accurate, it was undermined, particularly among 5‐year‐olds. Thus, by 4 years of age, children trust familiar informants but moderate that trust depending on the informants’ recent history of accuracy or inaccuracy.     

The cocktail party effect in infants

Most speech research with infants occurs in quiet laboratory rooms with no outside distractions. However, in the real world, speech directed to infants often occurs in the presence of other competing acoustic signals. To learn language, infants need to attend to their caregiver’s speech even under less than ideal listening conditions. We examined 7.5-month-old infants’ abilities to selectively attend to a female talker’s voice when a male voice was talking simultaneously. In three experiments, infants heard a target voice repeating isolated words while a distractor voice spoke fluently at one of three different intensities. Subsequently, infants heard passages produced by the target voice containing either the familiar words or novel words. Infants listened longer to the familiar words when the target voice was 10 dB or 5 dB more intense than the distractor, but not when the two voices were equally intense. In a fourth experiment, the assignment of words and passages to the familiarization and testing phases was reversed so that the passages and distractors were presented simultaneously during familiarization, and the infants were tested on the familiar and unfamiliar isolated words. During familiarization, the passages were 10 dB more intense than the distractors. The results suggest that this may be at the limits of what infants at this age can do in separating two different streams of speech. In conclusion, infants have some capacity to extract information from speech even in the face of a competing acoustic voice.     

Rapid fast-mapping abilities in 2-year-olds

Learning a new word consists of two primary tasks that have often been conflated into a single process: referent selection, in which a child must determine the correct referent of a novel label, and referent retention, which is the ability to store this newly formed label-object mapping in memory for later use. In addition, children must be capable of performing these tasks rapidly and repeatedly as they are frequently exposed to novel words during the course of natural conversation. Here we used a preferential pointing task to investigate 2-year-olds’ (N = 72) ability to infer the referent of a novel noun from a single ambiguous exposure and their ability to retain this mapping over time. Children were asked to identify the referent of a novel label on six critical trials distributed throughout the course of a 10-min study involving many familiar and novel objects. On these critical trials, images of a known object and a novel object (e.g., a ball and a nameless artifact constructed in the laboratory) appeared on two computer screens and a voice asked children to “point at the _____ [e.g., glark].” Following label onset, children were allowed only 3 s during which to infer the correct referent, point at it, and potentially store this new word-object mapping. In a final posttest trial, all previously labeled novel objects appeared and children were asked to point to one of them (e.g., “Can you find the glark?”). To succeed, children needed to have initially mapped the novel labels correctly and retained these mappings over the course of the study. Despite the difficult demands of the current task, children successfully identified the target object on the retention trial. We conclude that 2-year-olds are able to fast map novel nouns during a brief single exposure under ambiguous labeling conditions.     

Novelty assessment in the brain and long-term memory encoding

Recent positron emission tomography (PET) studies have identified neuronal components of widespread novelty-assessment networks in the brain. We propose that the efficacy of encoding on-line information into long-term memory depends on the novelty of the information as determined by these networks, and report a test of this “novelty/encoding” hypothesis. Subjects studied a list of words. Half of the words were “familiar” by virtue of their repeated presentation to the subjects before the study of the critical list; the other half were novel, in that they had not previously been encountered in the experiment. The results conformed to the prediction of the novelty/encoding hypothesis: accuracy of explicit (episodic) recognition was higher for novel than for familiar words.     

Preschoolers monitor the relative accuracy of informants

In 2 studies, the sensitivity of 3- and 4-year-olds to the previous accuracy of informants was assessed. Children viewed films in which 2 informants labeled familiar objects with differential accuracy (across the 2 experiments, children were exposed to the following rates of accuracy by the more and less accurate informants, respectively: 100% vs. 0%, 100% vs. 25%, 75% vs. 0%, and 75% vs. 25%). Next, children watched films in which the same 2 informants provided conflicting novel labels for unfamiliar objects. Children were asked to indicate which of the 2 labels was associated with each object. Three-year-olds trusted the more accurate informant only in conditions in which 1 of the 2 informants had been 100% accurate, whereas 4-year-olds trusted the more accurate informant in all conditions tested. These results suggest that 3-year-olds mistrust informants who make a single error, whereas 4-year-olds track the relative frequency of errors when deciding whom to trust.